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Providing straightforward information pertaining to drugs, drug use & drug policy. The Grey Pages promotes drug-related literacy and advocates a system of viable and tolerant drug policies. This is my personal collection of commentaries, essays, tid-bits, and other such writings on everything ranging from drug use, drug policy and drug-myths, to drug-science, addiction, human behavior, and the workings of the human brain. I started this blog with a particular focus on opioids, and over the past year have found my interest gravitate toward the intriguing, ever-changing world of designer intoxicants (i.e. "research chemicals" or "designer drugs").

Saturday, August 20, 2011

Narcotics and Psychological Dependence

Primer on Dopamine & Mesolymbic Reward

Cocaine, methamphetamine, MDMA, alcohol, benzodiazepines, morphine or heroin; Nearly all psychoactive drugs have one major action in common; that is to directly or indirectly increase the firing of dopamine from the ventral tegmental area (or VTA) into the nucleus accumbens (an area known as a key pleasure center of the brain). These areas comprise 2 components of a functional system known as the brain's reward system, also known as the mesolimbic dopamine system.

Elevation in limbic dopamine is a natural, not to mention vital, function of the brain, and plays a major role in motivation, through positive reinforcement of certain behaviors such as eating or sex. Dopamine plays a dominant role in mediating our sense of motivation, urge, and desire.

To put it simply; synaptic transmission of dopamine is the brain's way of rewarding an individual for certain activities, which in many cases are evolutionarily essential components of survival - The brain rewards human behavior much like one rewards a dog with a bone. Just as a dog is eventually trained to "sit, shake, lie down", the brain is trained to depend on these rewarded behaviors; in turn we become motivated to eat, drink, excercise, have sex, pursue a partner or pursue a personal passion.

Cortical connections between reward and memory are formed over time through a process of synaptic adaptation, or, the strengthening of connections between neural pathways. These changes in the long term affect motivation & instinct. In essence, by the time a human has fully developed in most ways which are relevant, he/she has become psychologically dependent on a myriad of seemingly rudimentary, everyday tasks. Even our indulgent, non-essential personal habits or vices, whatever they may be; dancing, gambling, smoking, eating, spending, stealing, have become psychological dependencies which the instinctual drive often believes are necessary to survival (as the primitive limbic brain cannot distinguish want from need).

These habits may or may not be essential to survival, and may or may not be healthy or constructive. They may or may not have negative impacts on us socially, occupationally, financially, or behaviorally. Most individuals will maintain a level of good judgement and responsibility; however some individuals by nature or character tend to act impulsively, and without a great deal of regard for the potential impact of such behavior. This may often be referred to as a compulsive or "addictive" personality. This individual is more likely than others to develop a pattern of problematic or destructive behavior.

Are opioids addictive?

In some cases yes. Just as any other reinforcing activity is potentially "addictive". However, a compulsive habit does not develop overnight. To the contrary, it generally takes a great deal of work to develop an instinctual desire for opioids; and no one inadvertently finds themselves in this situation. As discussed earlier, opioids can be just as reinforcing to the brain as food, sex, or money. Additionally, their physiological and emotional effects are extremely pleasant to most users.

The psychological dependence liability of opioids, as with other drugs, is mediated by this very reinforcement mechanism; the limbic dopamine regions of the VTA & nucleus accumbens; the same circuitry which mediates much of the euphoric sense of well being provided by a mu opioid agonist.

When opioids are used habitually, and in excess doses, their rewarding & reinforcing effects prime the brain to prioritize this particular behavior, much as it would eating (see dopamine above). Cortical connections are eventually formed, incorporating drug taking as a 'prioritized behavior'. Opioid use becomes an instinctual urge much like love or sex, and in addicted individuals will often take precedence over these everyday tasks, including eating and self care. But while the brain craves the use of an opiate, the conscious or "rational" mind exhibits control over impulse, leaving one the choice to either resist or to satisfy the urge. Just as sexual desire may be hard to resist, most of us do not allow these urges to control our behavior; however, the pleasure of opioids much like the pleasure of sex, serve as sufficient motivation for some to continue habitual use despite negative results.

Is addiction involuntary?

Addiction is not a disease and addiction is certainly not involuntary. Likewise, the addict is not a victim. Despite an instinctual urge, continued use in this situation is a conscious choice. Many regular users (if not a majority) will likely simply choose to use narcotics, even when this choice is not in their current best interest. They are simply that pleasant, not to mention that reinforcing. As cortical connections of opioid use have made this behavior as high a priority as sex, money, or food - to simply give up narcotics may be no easier than giving up a heated relationship, or refusing a fat stack of cash. It is simly an instinctual insult, much like refusing to eat good tasting food, or to have ones dick sucked. Narcotic use is reinforcing in the same way as virtually any other vital or hedonistic behavior; in fact, if opioids did not produce reinforcement, the brain would not "learn" to transmit endogenous opioids (endorphins) in response to pain or injury, thus stripping the body's ability to naturally regulate pain.

The only involuntary component of habitual narcotic use is the biological reinforcement itself, which is merely a motivational factor. The behavior alone, like all other conscious behavior, is mediated completely by the higher functioning brain (i.e. the conscious mind). Simply put, drug use in an "addict" is a choice, mediated by ones own will. For an opioid addict to stop or reduce their use may not be an easy task, just as any reinforcing habit. However, it can be, and is, done by many people. Some may face an eventual crossroads, some may find something which provides greater fulfillment, and some may become tired of the social and financial hassle, while others may sacrifice their habit to the wishes of a loved one.

On the other hand, those who choose to indulge in narcotics have every right to that choice; but would be childish and delusional to play the role of medical "victim" in the face of repercussions of their own poor choices and incompetence. Must I state the obvious by saying that "addicts" use opiates because they find great pleasure in it? It should not be dissicult to grasp that; those who sacrifice much of their world for a drug habit, do so because they find comfort in narcotic induced elation & contentment. Is this news? Value is subjective; what the status quo dictates as meaningless, another will find of great importance. Just as much of the things which popular culture finds essential to life such as money, cars, love and reproducing, is of little to no value to the narcotic dependent.

Does a drug-related addiction last a lifetime?

The answer is much more complicated than a simple yes or no. Bearing in mind that addiction is not a disease, but a deeply reinforced behavioral pattern or habit, the act of habitual drug use can be broken by anyone who chooses to do so.

In terms of the brain - by linking specific behavioral, sensory and environmental stimuli to specific memory storage sites, and further linking emotional processing into the equation, the brain has the ability to form memories, passions, personal meanings and sentiments which remain written into the brain for years to a lifetime. A chronic habitual drug user will likely always have memories of cocaine use, along with their own feelings associated with such memories. Furthermore, their may even remain positive sentiments or passions associated with drug use. This is dependent on one's personal experience with drug use and their own interpretation of the subjective effects of a drug.

On the other hand; other circuitry of the brain has the remarkable ability to revert to its original state of function (i.e. ability to maintain homeostasis). This includes much of the "base brain" circuitry associated with reward, reinforcement and obsession or compulsion. Drug related "psychodependence" - the phenomena which leads one to reward seeking behavior - fades with drug moderation or a period of abstinence. The absence of this phenomenon allows the subsequent habit to be much more easily broken, just as any other obsessive or compulsive habit. Depending on the length of ones habit and ones level of attatchement & reliance upon a given drug, this can take anywhere from weeks to months.